This invention relates to tape transports, and particularly to such transports having directional controls for the tape-coiling reels thereof.
Tape transports usually have hand-operable switches controlling a capstan and supply and takeup reels to move the tape in a forward direction during play and record modes of operation, and in reverse direction during the rewind mode, when the tape is uncoiled from the takeup reel and re-coiled upon the supply reel for return to storage in a ready condition for replay at some future time. Usually the supply reel is on the left, as viewed by the operator, and rotates in an counter clockwise direction during forward transport, the tape coming off in a downward direction and making a U-shaped loop past the transducing heads and up again to the takeup reel, which rotates in the same counter clockwise direction; and during rewind mode the dlrection is reversed, and both reels rotate in a clockwise direction. In both modes, the tape is coiled with the oxide or recorded information side radially inward on the reel, for the better protection of the information.
However, some very compact and light-weight machines are used for field work, and although they process the tape interchangeably with the heavier studio or laboratory machines, the field machines may use the so-called "Z" shaped path, which is better adapted for compact arrangement than the "U" shaped path. The supply reel on a Z-coiling machine is still coiled with the oxide side radially inward, for interchangeability with U-coil machines, and the supply reel rotational direction is still counter clockwise for forward play-record and clockwise for rewind mode. However, the tape path is arranged generally diagonally between the reels, like the middle portion of a "Z" or an "N", and the takeup reel rotates clockwise for forward play-record and counter clockwise for rewind, with the result that the tape on the takeup reel is coiled with the oxide radially outward in the tape pack. So long as some care is exercised while the tape is on the takeup reel, the damage risk is acceptable as a price for the more compact tape path.
Field transports are generally battery-operated, however, and when the transports are being used for recording live news events or on-going experiments, it becomes economical in both battery use and time use to record only in the field, then set the takeup reel aside and rewind it later on a studio "U" machine.
It has therefore become convenient to equip such a U-coiling studio machine with another switch, separate from that which changes the tape direction between play-record and rewind modes, the extra switch being used only to change the rotational direction of the takeup reel from clockwise to counter clockwise during rewind, thus transforming the machine into a Z-coiling machine temporarily.
When such a rewind switch is used, however, it is easy for the operator to become confused, and to set the switch for the wrong direction for the reel that he is rewinding; or he may forget to reset the switch for U-coil operation after he has rewound a Z-coil reel.
Accordingly, it is an object of the present invention to provide a directional-control rewind switch for a takeup reel motor that cannot easily be operated without correct coordination between the tape coil direction and the reel rotational direction.